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TABLES FOR FINDING THE DAY OF THE WEEK FOR KNOWN DATES.
By S. Hart Wright, M.D., A.M., Ph.D.

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The first seven letters of the alphabet, in numerical order, "Dominical Letters," or have long been used in almanacs as Sunday letters, to indicate what day of the week the year begins on. The days on which consecutive years begin are in the reverse order of the Sunday letters, A, B, C, D, E, F, G, and these show the days of the week for Jan. 1 as follows: A, Sunday, B, Saturday, C, Friday, D, Thursday, E, Wednesday, F, Tuesday, and G, Monday.

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Table 1 If the year is a leap-year, there must be two letters for it; the left-hand letter must be used for Jan. and Feb. only, and the other letter used for the other ten months. A table of Dominical Letters affords a very The Julian simple and ready method of finding the day of the week, of any day of any month, in any year. gives the dominical letters for the "Gregorian Style," now in general use, beginning in the Catholic States This was not adopted by England until 1752, and Russia not until 1901. of Europe in 1582. Calendar, or "Old Style," as now designated, was founded by Julius Cæsar, and began with the year 45 B. C. It assumed the civil year to be just 365 days long, which was 11 minutes too much, and every fourth year There was of 366 days. In 1582 this error amounted to 10 days, and Oct. 5th was counted 15th. The history of the world, from 45 B. C., to 1582, over 1600 years, is very largely recorded in the old style dates. That these dates may be put into week-days for the convenience of students of history, Table 2 is given above. Table 3 can be used in both "Old and New Style." In this are no dates in this style prior to 45 B. C. Table the Sundays in any month are under the Dominical Letter for the year given, and in the vertical column opposite to the month given, and once knowing the Sundays, the other days are mentally obtained.

EXAMPLE: On what day of the week did Columbus discover America (San Salvador), Oct. 12, 1492? This being an "old style" date, Table 2 must be used. Under the Centurial 1400, and at the right of 92 are In Table 3, under G, the 14th of Oct. is found to be Sunday, and hence the the letters AG (a leap-year). 12th was Friday, the day sought. When the given year has two letters, the first applies only to Jan, and Feb. Therefore G is used in this case.

EXAMPLE: On what day of the week was Abraham Lincoln shot, April 14th, 1865? This is a New Style Under the Centurial year 1800, and opposite 65 is A, and in Table 3 under date, and Table 1 must be used. A the 16th of April is found to be Sunday, hence the 14th was Friday, the day wanted, and by a strange coincidence it was "Good Friday" of Church days.

THE MOON'S AGE, NEW AND FULL,

FULL, FROM 1738 By S. Hart Wright, M.D., A.M., Ph.D.

TO 1946.

YEARS.

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1750

1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884] 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896) 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946

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Sep. Nov Mar. May Jun July Aug. Oct. Dec.

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Planets Brightest or Best Seen.

MERCURY, about February 20 and October 18, rising shortly before the sun; also about April 21 and September 13, setting shortly after the sun. VENUS, August 12 and October 24. MARS, March 29. JUPITER, September 12. SATURN, July 30. URANUS, June 15, and NEPTUNE, December 27. Notes.-MERCURY, when brightest, will rise and set as follows for lat. New York:

Rises, February 20, 5:36 a. m., December 17° 49′ S., or about 6° S. of sunrise point, and 20 m. after be ginning of twilight. Rises, October 18, 4:44 a. m., December 0° 44' S., or about 10° S. of sunrise point, and at the be ginning of twilight.

Sets, April 21, 7:31 p. m., December 15° 36' N., or about 12° S. of sunset point, and 52 m. before close of twilight.

Sets, September 13, 6:54 p. m., December 9° 11' S., or about 13° S. of sunset point, and 53 m. before close of twilight.

He will reach his greatest elongation west of the sun (27) February 27 and October 18 (18").
He will reach his greatest elongation east of the sun (22) May 10 and September 7 (27°).
The elongations chosen are only those nearest to the times of his greatest brilliancy.

Few people ever see Mercury, yet he can readily be seen when looked for at the right time by knowing where to look. Pick out the brightest and reddest star-like body in the vicinity indicated above and you have it. As a further means of identification we will add that on February 20 he will be 15 S. of the A in Aquarius; on October 18, 10° N. and a little west of Spica Virginis; .on April 21 in Aries, and a line drawn through the two southern stars of the square of Pegasus to the eastern horizon will hit him; on September 13 he is 5° east of Spica Virginis.

VENUS has two dates when she will be brighter than any of the other planets or stars. On the latter date, October 24, she will perhaps appear to the best advantage owing to a lesser amount of moonlight, but she will be very bright for a considerable time before and after these dates. On the first date, August 12, she will be an evening star, and October 24 a morning star. A small telescope or good field glass will show her as a beautiful crescent, not unlike that of the moon just before and after new moon. She will also increase and decrease in apparent size as she approaches or recédes from us. All of these features are shown in the annexed figure."

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A-15 days after superior conjunction, July 8, 1904.
Apparent diameter, 10".

B-At greatest elongation west, November 28, 1903.
Apparent diameter, 24".

C-When brightest, October 24, 1903. Apparent
diameter, 40".

D--Just after inferior conjunction, September 20, 1903. Apparent diameter, 60".

E-15 days before superior conjunction, July 8, 1904. Apparent diameter, 10".

F-At greatest elongation east, July 9, 1903. Apparent diameter, 24".

G-When brightest, August 12, 1903. Apparent diameter, 38".

H-Just before inferior conjunction, September 20,

1903. Apparent diameter, 60".

At the time of her greatest angular distance from the sun (elongation) eastward she will ap pear exactly like a half moon, or the moon at one of the quarters, with the illuminated half toward the sun, as must always be the case. Later, as she approaches the sun in angular distance, and therefore sets earlier, she is also nearing the earth. Hence her apparent diameter or size, as well as brilliancy, will be increased. This will continue until August 12, when she will be brightest. Later on, September 17, she will be nearer still to us, at inferior conjunction, or between us and the sun. She has her greatest apparent diameter at that time, being nearest, yet she will be invisible, as she will be in line with the sun and earth. Nevertheless only a few days before and after that date she may be seen as a beautiful crescent, as a morning star before and an evening star after. Before July 9 and after November 28 she will grow dimmer and smaller, and present a gibbous phase. As she approaches her point of superior conjunction her illuminated portion becomes more nearly round, and she will be seen in the west at sunrise and in the east at sunset, yet will she be dim, because so far from us. See her movement through the constellations as given each month of the calendar pages; also her rising and setting.

MARS is an interesting object only when near his opposition in March and April this year. On March 29 he will rise at sunset and set at sunrise. While he will be brightest of the year at this time, he is sometimes still brighter. This will be the case when he comes to his opposition on or about the time of its perihelion at or near the earth's aphelion. These conditions will eventuate in 1907, as they did in 1892. The two tiny satellites, Deimos and Phobos, are only to be seen under the most favorable conditions and by the aid of the best telescopes.

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JUPITER at his brightest is a beautiful object, but the chief interest lies in his five satellites, four of which are to be seen by the aid of a very small telescope or good field glass. Such a glass will also show the peculiar equatorial zones or belts. The spectroscope has demonstrated that Jupiter is a semi-sun, or shines partially by his own light. The satellites will not show well until April. It is very interesting to watch them as they suddenly drop out of sight-eclipsed-as they pass into the shadow of the planet or reappear as they come out of it. Or as they make their transits across his face, followed or preceded by their shadows thrown on the bright disk of the planet. We give herewith a table of such of these phenomena as are visible from the 10th to the 20th of October, when the light of the moon will not be sufflcient to prevent good vision and Jupiter will pass the meridian at a convenient hour of the evening. For the purpose of illustration, take the series of phenomena within the braces: When Sat. I. disappears on the west side it passes behind the planet, and instead of reappearing at the east limb of the planet it is not seen again until some distance east of it, having passed into the shadow of Jupiter, hence, its next reappearance is from an eclipse. Then the Sat. passes around and moves across the planet-transit-between us and the planet, and from east to west (left to right), and 48 minutes later (8:56) the shadow of the Sat. may be seen moving across Jupiter's disk. Then the Sat. passes off at the west, and 48 minutes later its shadow does the same. The inhabitants of Jupiter are treated to about 900 of these events in the course of a Jovian year.

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SATURN is also a very attractive celestial object, but requires a telescope of fair power to distinguish the wonderful system of satellites and rings. His rings were most favorably observed last in 1899 and will be again in 1914 and in 1906.

URANUS can barely be seen with the naked eye, in the absence of the moon and by knowing just where to look. NEPTUNE is only to be seen by the aid of the best telescopes and favorable conditions. A first-class 2 or 3 inch (aperture) telescope will show him at opposition with good atmospheric conditions.

A Cable of Easter Days for Fifty Years.

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In the ancient Roman form of notation the principal symbols used were I.. which stood as the equivalent of the Arabic, 1; V., which stood for 5; X., for 10; L., for 50; C., for 100; D., for 500, and M., for 1,000. In order to express a series of numbers these symbols were combined according to the following rule: When the two letters, which were written one after the other, were intended to be added together, the symbol which represented a number which was equal to or greater than that represented by the other occupled the first position in the line, while the appearance of the lesser number in the first position denoted that its value was to be subtracted from that of the greater. Thus, for example, while XI. stood for 10 plus 1. or 11. IX. stood for 10 minus 1. or 9.

While it is not customary, at the present time, to make use of the Roman numerals except in the expression of dates, or for marking divisions in books, pamphlets, documents, etc., the Roman notation may be used in writing any combination of numbers, as a horizontal line placed directly above any symbol adds to its value one thousand times. Thus, while V. is the symbol for 5, v. stands for one thousand times 5, or 5,000.

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Highest test for a good telescope. Beautiful double-Yellow
and Green d 11".

Delicate and difficult D. P. d 19.5.

The "Wonderful"-Remains at brightest only 10 days.
Variable. Period 3314 days. 2d to 10th Mag.

13 Double-d 29s.6. Y. and pale gray.

10 Variable. Period 2d, 20h. 48m. 2d to 4th Mag.
Fine Star. D. d 75". In segment of Perseus.

29 Pleiades or Seven Stars. D. W. d 115".
58 In the V or Hyades-Red Star. D. d 107".9 B.
14 T. a. W. b. B, d 165". C. Gray d 450".

31 Below the belt. D. B.-Good test for 3 or 4 in. telescope.
52 Tip of N. horn. D. G. d 14s.5.

59 The upper one of the belt-a wide double. W.

"The Kings"-"Ell and Yard"--"Belt of Orion." D.
The middle of the 3 stars-Belt-3° long.
Merid. Alt. 16° Lat. N. Y.

26 10° S. of Belt of Orion-Midway to the 'Hare.
26 A remarkable variable.

53 Fine Star. D. B. d 185".

D. d 10"-a severe test owing to the great light of S.
7 D. com. violet d 21s.

11 D. d 4".9. G.-Finest double in northern heavens.
19 D. and Var. com. orange tinge d 145".

50 This, with Castor, points to Praesepe, in Cancer, 20" S. E.
{T or M. Companions gray and lilac.

31 The "Solitary One"-Variable. D. G. d 285". 44 Splendid. At end of handle of Sickle. D. P. d 176". Merid. Alt. S. Fla. 2°.

The brightest of "The Pointers" to Pole Star. D. Y. d 381". 54 On Lion's tail. D. P. d 176".

Just visible in extreme S. Fla. and Tex. T.

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